Multiplex analysis based on encoded particles has attracted great attention in high throughput biomolecule screening such as drug discovery and clinical diagnostics due to its expandability and fast reactivity. The multiplex analysis may be accomplished by mixing many encoded probe particles together in the same space containing target analytes.
In various samples, it is necessary to use a large number of distinct codes to increase throughput. To ensure a sufficiently large number of codes for microparticles, a spectral encoding method using coloring materials such as quantum dots or fluorescent dyes, which are embedded inside or attached on the surface of the microparticle and a graphical encoding method based on patterning of an optically detectable elements on the surface of the microparticle have been suggested.